CN108947939B

CN108947939B - Method for synthesizing terpinolene 4, 8-epoxide

Info

Publication number: CN108947939B
Application number: CN201810936312.1A
Authority: CN
Inventors: 郑辉东; 黄元斌; 赵素英; 王莹淑; 曾燕茹
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2018-08-16
Filing date: 2018-08-16
Publication date: 2022-03-11
Anticipated expiration: 2038-08-16
Also published as: CN108947939A

Abstract

The invention discloses a method for synthesizing terpinolene 4, 8-epoxide, which takes the downstream product of turpentine, i.e. terpinolene, as a raw material, and the method comprises the steps of uniformly mixing the raw material with a solvent, a catalyst and a catalyst auxiliary agent, and then reacting the mixture with a solution containing an oxidant, i.e. hydrogen peroxide, to synthesize the terpinolene 4, 8-epoxide. The catalytic oxidation system adopted by the invention has high oxidation selectivity, the catalyst is easy to recover, the used reagent is environment-friendly, the process is safe, and the method is suitable for industrial production. Under the optimal conditions of the experiment, the conversion rate of the terpinene can reach more than 95%, and the product selectivity is more than 85%.

Description

Method for synthesizing terpinolene 4, 8-epoxide

Technical Field

The invention belongs to the technical field of organic synthesis, and particularly relates to a method for synthesizing terpinene 4, 8-epoxide.

Background

Terpinene-4-ol has high added value and is often used as a component for synthesizing essence and flavor, but due to the uncertainty of supplying the terpinene-4-ol by taking natural plants as raw materials, the terpinene-4, 8-epoxide obtained by the epoxidation route of the terpinene is often industrially subjected to further reaction to obtain the terpinene-4-ol, however, the epoxidation reaction of the terpinene is always a bottleneck of the industrial production route. The carbon of the 1 and 4 positions of the terpinene has double bonds (the structural formula is shown as the following), so that the property is very active, the terpinene 1,2-4, 8-diepoxide is easily and completely oxidized, and the selectivity of the reaction is reduced; the double bond has stronger reaction activity, and a series of reactions such as isomerization, polymerization, double bond fracture and the like are easy to occur under certain conditions, so that the reaction process is difficult to control, which is also the main technical difficulty of the synthesis of the current terpinolene 4, 8-epoxide.

It is stated in US 3676504 that an terpinolene starting material may be subjected to epoxidation using an organic peroxy acid, such as peracetic acid, peroxopropionic acid or m-chloroperoxybenzoic acid, as the oxidant and methylene chloride as the solvent. However, the oxidation reaction with peroxy acids usually gives off a lot of heat, often requires appropriate cooling and dilution to prevent explosion, and the reaction process is not easy to control, which results in low yield and is not suitable for industrialization.

In international patent WO 2016180642, a hexachloroacetone-pyridine-hydrogen peroxide catalytic system is used, and toluene is used as a solvent to perform an terpinolene epoxidation reaction. Wherein, hexachloroacetone is expensive and is easy to hydrolyze in the reaction process to generate trichloromethane and trichloroacetic acid, so that the catalyst is difficult to recover; in addition, pyridine has a bad odor and is highly toxic. Joos Wahlen et al use hydrogen peroxide as an oxidant and phenol as a solvent for olefin epoxidation and add sodium acetate to inhibit product ring opening. However, high-boiling polymers are formed in the course of the reaction, and a large amount of phenol is also used. The two methods lead to high difficulty in subsequent wastewater treatment, difficult standard discharge and easy water pollution.

Xi Zuiwei subject group reported as H₂O₂Long-chain quaternary ammonium salt type phosphotungstic acid heteropoly salt compound Q is used as an oxygen source under mild conditions₃[PW₄O₁₆](Q = quaternary ammonium salts, e.g. [ pi-C ]₅H₅N⁺(CH₂)₁₅CH₃Cl]Etc.), but this method is used for the epoxidation of terpinene, and it is difficult to control the activity of the reaction, and a complete oxidation reaction is liable to occur, and the selectivity is poor.

In summary, a safe, environment-friendly, mild reaction conditions and high oxidation selectivity terpinene 4, 8-epoxide synthesis process needs to be explored, and the process needs to be simple and is suitable for industrial production.

Disclosure of Invention

The invention aims to provide a method for synthesizing terpinene 4, 8-epoxide, aiming at solving the problems of harsh reaction conditions, difficult catalyst recovery, waste water pollution, poor oxidation selectivity and the like in the existing terpinene epoxidation reaction. The reaction system involved in the method has mild reaction conditions, recyclable catalyst, high oxidation selectivity, simple product separation, easy treatment and recovery of waste liquid and less side reactions.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for synthesizing terpinene 4, 8-epoxide is characterized in that a terpinene raw material, a catalyst auxiliary agent and a solvent are mixed and stirred uniformly to form a mixture solution, and then the mixture solution and a hydrogen peroxide solution are further mixed and reacted in a reactor to generate the terpinene 4, 8-epoxide.

The mass fraction of the terpinene in the terpinene raw material is 80-95%.

The molar ratio of the used catalyst to the terpinene raw material is 0.15-0.3; the catalyst comprises any one of 2,2, 2-trifluoro acetophenone, 1,1, 1-trifluoro acetone, hexafluoroacetophenon, perfluoroacetone or p-fluoro acetone.

The molar ratio of the catalyst promoter to the terpinene raw material is 1.3-3.0; the catalyst auxiliary agent comprises any one of acetonitrile, propionitrile or butyronitrile.

The molar ratio of the used solvent to the terpinene raw material is 0.6-2.0; the solvent comprises any one of benzene, toluene, ethylbenzene, xylene or trimethylbenzene.

The molar ratio of the hydrogen peroxide solution to the terpinene raw material is 1.8-2.7; the mass fraction of hydrogen peroxide in the hydrogen peroxide solution is 30-80%.

When a batch reactor is used as a reactor for reaction, the hydrogen peroxide solution is dropwise added into the mixed raw material solution for 1-3h, the reaction temperature is 20-40 ℃, and the total reaction time is 9-12 h.

When the micro-channel continuous reactor is used as a reactor for reaction, the hydrogen peroxide solution and the mixture solution are respectively and simultaneously added into the micro-channel continuous reactor through different channels, the reaction temperature is 60-80 ℃, the reaction pressure is 0.3-0.7MPa, and the reaction residence time is 8-10 min.

The invention has the advantages that:

1) the invention overcomes the defects of the prior art, the catalyst has stable property and is not decomposed in the epoxidation reaction process, the catalyst can be recovered by vacuum rectification after the reaction is finished and can be recycled, the invention has obvious advantages in the aspect of industrial cost, and the problem that the catalytic system is easy to hydrolyze in the prior reaction process is solved.

2) After the epoxidation reaction is finished and the reactor is kept stand, the product can be automatically separated into oil and water, the oil phase is a reaction product, and the water phase mainly contains water, a catalyst auxiliary agent and residual hydrogen peroxide in the reaction. The hydrogen peroxide in the water phase is treated by adding the sodium sulfite aqueous solution, and the dichloromethane is added to extract the catalyst auxiliary agent, so that the obtained wastewater is simple to treat and easy to reach the standard for discharge, meets the environmental protection requirement, solves the problem of water treatment in the existing epoxidation reaction system, and can be recycled.

3) The reaction system adopted by the invention has moderate oxidizability and mild reaction conditions, can directionally oxidize the double bond at the 4 th position, has higher oxidation selectivity, and finally has the highest selectivity on the target product terpinene 4, 8-epoxide up to more than 85 percent.

4) The epoxidation reaction can be carried out in the batch kettle type reactor, the reaction condition is mild, a complex cooling system is not needed, the energy consumption is low, the requirement on equipment is low, and the equipment investment is low; the method can also be carried out in a continuous microchannel reactor, the heat release of the reaction is larger due to the adoption of hydrogen peroxide as an oxidant, the heat of the reaction can be removed in time by adopting the microchannel reactor, the safety of the reaction process is greatly improved, and meanwhile, the reaction rate is greatly improved by strengthening mass transfer.

5) The reagents used in the epoxidation reaction are all safe and environment-friendly, the catalyst auxiliary agent and the solvent involved in the reaction can be recycled, and the wastewater is not easy to cause pollution.

6) The method has high selectivity and yield of the target product terpinene-4, 8-epoxide, is easy to realize industrialization and is environment-friendly.

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.

Example 1

Uniformly mixing 10g of an terpinene raw material (mass fraction of 84%), 3g of 2,2, 2-trifluoro acetophenone, 5g of acetonitrile and 6g of toluene to obtain a mixture solution, transferring the mixture solution into a batch kettle type reactor, and slowly dropwise adding 10g of a 50% hydrogen peroxide solution into the mixture solution at 30 ℃ for 2 hours. And after the dropwise addition is finished, continuously stirring and reacting for 9 hours, standing, collecting an organic phase and a water phase respectively after the mixed solution is layered, adding 9g of sodium sulfite solution (mass fraction is 15%) into the organic phase, stirring for 30min, removing the residual hydrogen peroxide, and sampling the residual organic phase for chromatographic analysis.

Example 2

100g of an terpinene raw material (mass fraction: 84%), 25g of 2,2, 2-trifluoro acetophenone, 50g of acetonitrile and 50g of toluene are uniformly mixed to obtain a mixture solution, the mixture solution is transferred to a batch kettle type reactor, and 180g of a 30% hydrogen peroxide solution is slowly dripped into the mixture solution at 35 ℃, wherein the dripping time is 2 hours. And after the dropwise addition is finished, continuously stirring and reacting for 9 hours, standing, collecting an organic phase and a water phase respectively after the mixed solution is layered, adding 92.4g of sodium sulfite solution (mass fraction is 15%) into the organic phase, stirring for 30min, removing the residual hydrogen peroxide, and sampling the residual organic phase for chromatographic analysis.

Example 3

Hexafluoroacetone was used in place of 2,2, 2-trifluoroacetophenone used in example 1 in an amount of 2.9g, and the procedure was as in example 1.

Example 4

Propionitrile was used in place of the acetonitrile used in example 1, in an amount of 6.7g, and the procedure was as in example 1.

Example 5

Benzene was used in place of toluene used in example 1 in an amount of 5g, and the procedure was as in example 1.

Example 6

The 50% hydrogen peroxide solution used in example 1 was replaced with a 30% hydrogen peroxide solution in an amount of 16.5g, and the rest of the procedure was the same as in example 1.

Example 7

The reaction temperature was adjusted to 20 ℃ and the procedure was as in example 1.

Example 8

The dropping time was adjusted to 3 hours, and the rest of the procedure was the same as in example 1.

Example 9

100g of terpinene raw material (mass fraction 84%), 25g of 2,2, 2-trifluoro acetophenone, 50g of acetonitrile and 50g of toluene are mixed uniformly to obtain a mixture solution, the mixture solution and 180g of 30% hydrogen peroxide are added into a continuous microchannel reactor, the total flow is 30ml/min, the reaction temperature is 70 ℃, the reaction pressure is 0.5MPa, and the retention time is 8.7 min. Collecting reaction liquid at the outlet of the reactor into a three-neck flask placed in a cold trap, standing, after the mixed liquid is layered, respectively collecting an organic phase and a water phase, adding 92.4g of sodium sulfite solution (mass fraction is 15%) into the organic phase, stirring for 30min, removing residual hydrogen peroxide, and sampling the residual organic phase for chromatographic analysis.

Example 10

The reaction temperature was adjusted to 80 ℃ and the reaction pressure was adjusted to 0.7MPa, and the other steps were carried out in the same manner as in example 9.

Example 11

The residence time was adjusted to 10min and the procedure was as in example 9.

The experimental data obtained for examples 1-11 are shown in Table 1.

TABLE 1 results data Table

As can be seen from Table 1, the highest conversion rate of the terpinene and the highest selectivity of the product can reach 95% by adopting the method provided by the invention.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

Claims

1. A method for synthesizing terpinene 4, 8-epoxide is characterized in that: mixing and stirring an terpinene raw material, a catalyst auxiliary agent and a solvent uniformly to form a mixture solution, and then further mixing and reacting the obtained mixture solution and a hydrogen peroxide solution in a reactor to generate the terpinene 4, 8-epoxide;

the mass fraction of the terpinene in the terpinene raw material is 80-95%; the molar ratio of the used catalyst to the terpinene raw material is 0.15-0.3; the catalyst is any one of 2,2, 2-trifluoro acetophenone, 1,1, 1-trifluoro acetone, hexafluoroacetophenon, perfluoroacetone or p-fluoro acetone; the molar ratio of the catalyst promoter to the terpinene raw material is 1.3-3.0; the catalyst auxiliary agent is any one of acetonitrile, propionitrile or butyronitrile; the molar ratio of the used solvent to the terpinene raw material is 0.6-2.0; the solvent is any one of benzene, toluene, ethylbenzene, xylene or trimethylbenzene; the molar ratio of the hydrogen peroxide solution to the terpinene raw material is 1.8-2.7;

the mass fraction of hydrogen peroxide in the hydrogen peroxide solution is 30-80%.

2. The method of synthesizing terpinolene 4, 8-epoxide according to claim 1, characterized in that: the reactor is a batch kettle reactor.

3. The method of synthesizing terpinolene 4, 8-epoxide according to claim 2, characterized in that: when the batch reactor is adopted for reaction, the hydrogen peroxide solution is dropwise added into the mixture solution for reaction, the dropwise adding time is 1-3h, the reaction temperature is 20-40 ℃, and the total reaction time is 9-12 h.

4. The method of synthesizing terpinolene 4, 8-epoxide according to claim 1, characterized in that: the reactor is a microchannel continuous reactor.

5. The method of synthesizing terpinolene 4, 8-epoxide according to claim 4, characterized in that: when a continuous microchannel reactor is adopted for reaction, hydrogen peroxide solution and mixture solution are added simultaneously through different channels respectively, the reaction temperature is 60-80 ℃, the reaction pressure is 0.3-0.7MPa, and the reaction residence time is 8-10 min.